Cloud-based processing of remote sensing point clouds for instability mechanism analysis of coarse-grained deposit

Accurate assessment of dynamic reserves is essential for effective debris flow hazard mitigation. This study examines the influence of rainfall intensity and surface runoff on the failure behavior of coarse-grained skeletal deposits on debris flow gully banks through controlled indoor flume experiments. A variable-slope flume (14°), simulated rainfall (12–51 mm/h), and controlled runoff (0.426–1.810 m³/min) were employed, with deformation monitored via high-speed imaging and 3D laser scanning. Point cloud data were processed using CloudCompare and GIS platforms. The results reveal that: (1) flow rate is the dominant factor controlling instability scale, as the coarse-grained skeletal structure exhibits high sensitivity to scouring intensity; (2) failure initiates with toe erosion and free face development, followed by tensile cracking, cracks retrogress towards the slope cres, and cracks retrogress towards the slope cres; (3) the interaction between intense rainfall and high runoff generates a positive feedback loop that substantially enhances slope instability.